The invention relates to metering multiple fluids together. More particularly, the invention relates to a system and method for proportion metering multiple fluids together that are output from different pumps. The invention further relates to a system for batch signal metering that provides feedback on the amount of fluid that has been dispensed. The invention has applications in numerous technologies, including metering together pest control fluid, such as those used for termite control; metering lawn care fluids such as herbicide and fertilizer; blending colors used in dyes, paints and the like; personal care products such as lotions; water treatment; and other technologies in which different fluids are pumped by separate pumps and thereafter mixed together downstream of the pumps prior to being dispensed.
In the pest control industry today, termite control is achieved by injecting a mixture of water and one or more termiticide chemicals into spaced application holes or application areas. The most common proportioning method currently employed is to premix the water and termiticide in a large tank, with the mixture being pumped from the tank through an injection gun into the appropriate location. While relatively simple, an issue that arises is getting the correct proportion of water and termiticide mixed in the tank. This is difficult due to the fact that the tank is never completely emptied, so having to add a predetermined amount of termiticide to a predetermined amount of water so that the desired proportion is maintained in the tank becomes a guessing game.
An additional problem is knowing if the proper amount of mixture went into each application hole or into each application area. If it does not, a xe2x80x9cbridgexe2x80x9d will exist for termites to pass through. One way to measure the amount of mixture injected is to attach a flowmeter to the injection gun. However, the accuracy of flow-meters deteriorates during on-off triggering (i.e. transient) conditions of the injection gun. Accurate measuring of injected mixture is important, particularly when the chemical being injected is potentially harmful to the environment. Moreover, it is often difficult for an operator to keep track of the flowmeter while at the same time handling the application device and performing the tasks of the job.
Another method presently used to proportion water and termiticide is to use the pressure from a water hose to drive a piston reciprocator that in turn drives a metering piston pump for the termiticide. Such a device is supplied under the name xe2x80x9cInjecto-maticxe2x80x9d by HandH Holdings of Ontario, Canada. The problems with such a device include limited ranges, time required for mechanical adjustments, time for calibration, and time for service.
Perhaps the primary method currently used to proportion meter two or more fluids together is to use master-slave technology for pumps that are used to pump the fluids. One pump is the master, and the other(s) is slaved to its speed at the proper ratio. In a mechanically locked system, this slaving is held very close. But with this type of system, adequate mixing ratio accuracy""s can only be maintained up to about 10:1 because of changeover and valving effects. Electronically slaved pumps operated by servo motors have the additional problem of not being able to lock together very well, because the two pump systems will be xe2x80x9ctunedxe2x80x9d together at only one condition. Therefore, one pump will start and/or stop faster than the other. This happens each time the injection gun is turned on and off, which occurs frequently when injecting into the application holes.
One method to overcome this problem is the sequential metering system disclosed in U.S. Pat. No. 5,368,059. This patent discloses that a first fluid component is pumped in a mini-batch, followed by a second fluid component that is pumped in a mini-batch, followed by the first fluid component, etc. This concept requires specialized mixing devices in order to fully mix the two fluids.
Improvements in proportionally metering multiple fluids together that are output from different pumps would benefit a large number of industries. In addition, more accurate monitoring of dispensed fluids would provide an added benefit.
The invention provides a system and method for proportion metering multiple fluids together that are output from different pumps. The invention further provides a system and method for batch signal metering that provides feedback on the amount of fluid that has been dispensed. The invention has applications in numerous technologies, including metering together pest control fluids, such as those used for termite control; metering lawn care fluids such as herbicide and fertilizer; blending colors used in dyes, paints and the like; personal care products such as lotions; water treatment; and other technologies in which different fluids are pumped by separate pumps and thereafter mixed together downstream of the pumps prior to being dispensed.
In one aspect of the invention, a method of proportion metering first and second fluids is provided. The fluids are output from first and second pumps, respectively, over a continuous series of proportioning cycles to achieve a selected mix ratio. The method comprises: a) simultaneously operating the first and second pumps; b) monitoring the amounts of the first and second fluids output by the first and second pumps during each proportioning cycle, respectively; c) stopping the first pump while the second pump continues operating until the selected mix ratio is achieved for a current proportioning cycle, and then restarting the first pump to begin the next proportioning cycle; and d) continuously repeating step c) on a periodic basis.
In yet another aspect of the invention, a method of proportion metering first and second fluids output from first and second pumps to achieve a predetermined mix ratio is provided. The method comprises repeatedly pumping the first and second fluids in discrete batches through simultaneous operation of the first and second pumps, the ratio of the volumes of the first and second fluids in each batch equaling the predetermined mix ratio.
In another aspect of the invention, a method of controlling first and second pumps that output first and second fluids, respectively, in order to blend the first and second fluids in a selected mix ratio is provided. The method comprises simultaneously operating the first and second pumps over a series of repeating proportioning cycles to output the first and second fluids; monitoring the amounts of the first and second fluids output by the first and second pumps during each proportioning cycle; stopping operation of the first pump in each proportioning cycle while the second pump continues to operate, operation of the first pump being stopped each time the first pump outputs a selected amount of the first fluid; and restarting the first pump once the second pump has output enough of the second fluid in a current proportioning cycle to achieve the selected mix ratio.
In another aspect of the invention, a system for proportion metering fluids, comprises first and second pumps for pumping first and second fluids, respectively. Each pump includes a drive motor, and the fluid displacement of the first pump is less than the fluid displacement of the second pump. A sensor associated with each drive motor senses revolutions of each pump. Control circuitry is provided for determining the amounts of the first and second fluids output by the first and second pumps based upon the sensed revolutions during a series of repeating proportioning cycles. The control circuitry is designed to stop operation of the first pump when a predetermined amount of the first fluid has been output in each proportioning cycle. The control circuitry is further designed to restart operation of the first pump to begin the next proportioning cycle when the second pump outputs enough of the second fluid to achieve a desired mix ratio between the first and second fluids in each proportioning cycle.
In yet another aspect of the invention, a method of tracking the amount of fluid dispensed from a fluid dispensing system is provided. The method comprises selecting an incremental amount of fluid that is less than a total amount of fluid to be dispensed; electronically monitoring the amount of fluid being dispensed during dispensing; and electronically generating a sensory signal each time that the amount of fluid dispensed equals the incremental amount of fluid.
In yet another aspect of the invention, a system for tracking amounts of fluid dispensed from a fluid dispenser comprises means for selecting an incremental amount of fluid that is less than a total amount of fluid to be dispensed from the fluid dispenser, means for electronically monitoring the amount of fluid being dispensed from the fluid dispenser during dispensing; and means for electronically generating a sensory signal each time that the amount of fluid dispensed from the fluid dispenser equals the incremental amount of fluid.
An additional aspect of the invention provides a termite control system for use on a vehicle. The system includes a module mountable on the vehicle, with the module including first and second tanks containing first and second fluids, and first and second pumps having inlets connected to the first and second tanks, respectively, and outlets connected to an injection gun. A control system controls operation of the first and second pumps, with the control system permitting simultaneous operation of the first and second pumps, and where the first and second fluids are output from the injection gun as a mixture with a predetermined mix ratio.
Another aspect of the invention provides an assembly that is associated with a tailgate of a pickup truck for extending the box of the pickup truck. The assembly includes a rear panel that is pivotally connected at a first edge thereof to the tailgate whereby the rear panel is pivotable relative to the tailgate between a position generally perpendicular to the tailgate and a position generally parallel to the tailgate. In addition, the assembly includes first and second side panels pivotally connected at edges thereof to second and third edges of the rear panel whereby the first and second side panels are pivotable relative to the rear panel between positions generally perpendicular to the rear panel and positions generally parallel to the rear panel, and the second and third edges of the rear panel are generally perpendicular to the first edge.
One advantage of the invention is that accurate metering of termiticide and water is achieved to assure correct application per label instructions.
Another advantage is that consistent metering is provided under all conditions by removing the need for operator intervention to pre-mix fluid.
Yet another advantage is that audible batch size indication is provided to enhance the ability of the operator to dispense the correct amounts of fluid in application holes and other blind application situations. In addition, the system displays information concerning current or past jobs, as well as running totals of dispensed fluid amounts.
The invention further reduces chemical waste by up to 15% by mixing on demand, thereby providing consistent use of chemical for each job.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objects attained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying description, in which there is described a preferred embodiment of the invention.